A few years ago, the Washington Postreported that Maryland trains and buses are wired for audio as well as video surveillance, but officials weren’t then allowing audio surveillance. At the time, Maryland’s acting transportation secretary spoke out against audio surveillance. ”The [transportation] secretary believes that matters of public privacy are the ultimate test of people’s trust in government,” said her spokesman, Jack Cahalan. “We have tabled the matter.”

Now, the rules for audio surveillance of drivers and riders have changed on buses in Maryland’s Montgomery County, the Washington Postreports:

And on Montgomery County’s Ride On buses, the cameras do more than capture what they see. Many cameras also record what they hear, a little-known function that bothers civil liberties advocates. They see a creeping erosion of privacy in the growing use of audio recording technology on public transit.

The Maryland Transit Administration began audio recording in October on some buses in and around Baltimore and hopes to expand that to about half of the agency’s 700 buses by summer. […]

The stated intention of the systems on the nearly 300 Ride On buses with audio recording is to capture what drivers say. But the systems, which are always recording, are capable of picking up conversations of people sitting or standing near the drivers. A passenger talking to a spouse or child could end up being recorded, the snippet saved for several days on the system’s hard drive.

Some privacy experts say audio recording devices such as those on Ride On raise serious concerns. […]

George Washington University law professor Daniel J. Solove, author of “Understanding Privacy,” said recording a person during one commute might not seem particularly invasive. But with daily monitoring, “the totality of surveillance” can really add up, he said. […]

Stickers are posted on Ride On buses to alert riders about the recording devices on board. But having such a sticker or sign doesn’t mean a rider automatically forfeits privacy, in part because many riders have no choice but to use public transit, [said David Rocah, a staff attorney with the American Civil Liberties Union of Maryland].

The Post also notes other jurisdictions with audio and/or camera surveillance of public transportation riders:

In San Francisco, buses and trains have both audio and video recording, with the audio devices always running. And in Atlanta, transit officials are adding video and audio recording to buses and will put them on trains next. […]

Transit systems in New York City, Chicago and Philadelphia use video cameras on buses, but they do not record audio.